US1308820A - Process q- molding lenses - Google Patents

Description

E. D. THLYER AM] H. H4 STYLL.

PRDfiFSS 9F MOLDING LENSES APPLICATHUN FILED SEPT 6.19%.

1,308,820. Patented July 8, 1919.

1 E I f fwlmsssaszi yaw fHgfarD. Yiz'liyer and g Harry H. 5151! f f mdn m ma am Weir UNITED STATES PATENT OFFICE.

EDGAR D. TILLYER AND HARRY H. STYLL, OF SOUTI-IBRIDGE, MASSACHUSETTS,

ABSIGNOBS TO .QMERICAN OPTICAL COMPANY, OF SOUTHBRIDGE, MASSA- CHUSETTB, A. VOLUNTARY ASSOCIATION MASSACHUSETTS.

PROCESS O? MOLDING LENSES.

Specification of Letters Patent.

Patcutci'l July 8. 19.1.9.

Application filed September 8, 1916. Serial No. 118,773.

To all whom it may concern:

Be it known that we, EDGAR D. TILLYEXP and llnnnrH. STYLL, citizens of the United States, residing at Southbriclgc, in the county of lVorccster and Eitate of Massachusetts, have invented certain new and useful Improvements in Processes of Molding Lenses, of which the following is a specification.

This invention relates to improvements in method of ma'mifacturing ophthalmic lenses, and has for its leading object the provision of an improved sim )lified method of so molding or shaping op ithalmic lenses that at least one oi the molded surfaces shall pos sess a suilicicnt polish to be commercially usable as a lens without subsequent grinding or other operations thereon.

Av further object of the invention the provision of an im roved method by which a single complete y formed lens may be manufactured entirely by molding if desired, or by which a plurality of lenses may be ruzu'uifaetured in semi-finished form if preferred.

A. :t'urtlzer object of the invention is the provision of improved mechanism for carryin r out our novel method of. constructing o ihthalmic lenses.

Other objects and advantages of our im proved method of and apparatus for constructing ophthalmic lenses should he rcadily aimarcnt by reference to the following speci ication taken in connection with the accompanying drawings,and it will be understood that we may make any variations in the several steps of the process or in the machinery for carrying out the process, within the scope of the appended claims without in any Wise departing from or exceeding the spirit of our invention.

Figure I represents a fragmentary semidiagrammatic illustration of one step in the manufacture of the lens.

Fig. II represents a view of the blank heating and transferring means.

Fig. III represents a vertical sectional view illustrating one form of machine, which may be mployed in the carrying out of our invention.

Fig. IV represents an enlarged detail viewv of the air controlling valve.

Fig. V represents: a view of a spinning mold.

Referring especially to our novel process or method of forming ophthulnuc lenses by molding: We are aware that prior to our invention it has been customary to mold lumps or disks of glass into substantially the sha e of a finished lens, but hitherto these blah s have always had a rough, somcwluu pitted surface as brought from the mold, as a result of their contact with the mold. and consequently have not been usahie without suhsequent grinding. lVe i'urhcr miderstand that prior to our present invcnlion attmnpts hare heel: ma ls to polish. lenses and t en bend the same under influence of heat to vary the curve:- or shape of the lens Olin-h, This likewise has been. attended with considerable disadvantages. since the lenses so produced while in some inst noes due to the" use of exceptional care in their construction may have proved usable, have almost uni rcrsully been. rendered unfit for use a first class satisfacti'ary due to the factthat contact with the mold always to a greater or less degree injured the polished surface so that the surface was no longer a true lens surface, but was substantially impaired to render its use before the eye an unsatisfactory if not dangerous priiicedure, while on account of the difliculties attendant upon its even semi-sl'lccessiul operation, lenses could not he commercially prmlucerl in accordance with this process.

By the use of our present process, however, and by the interposition of a cushion or film of vapor between the face of the mold and the surface of the lens, the surface of the lens is in nowise injured or distorted by contact with the mold, but a fire polished surface produced which is rfeetly satisfac tory for a surface of an ophthalmic lens, and in all essential respects equal to a specially ground and polished lens surface.

In order that the carrying out of our proc ess may be better understood we have designed and herewith illustrated certain mechanism for the carrying out of the process, it being understood, however that the process is entirely independent of the particular machinery here illustrated, since we realize that other machinery or apparatus could be employed with equally satisfactory results, and the essential invention residing n the up )rcciatiou of the fact the a satisfactory sur ace could be produced on an ophthalmio lens by molding and in the process of production of this surface.

Referring to the apparatus for carrying out our JIOCGSS, as illustrated in the drawings, an in which similar characters of reference are employed to denote corresponding parts throughout the views, the numeral 1 designates a base mold section which has an upper surface 2 of the desired curve to be produced on the lens, said surface 2 being suitably coated with a thin layer of asbestos or other suitable absorbent material 3 having its inner face shaped to the exact curve to be produced on the lens. Disposed above the mold section 1 We have shown the plunger 4, which if desired may have the second curved surface 5 with the coating 6 to engage and shape the upper face of the lens.

It will be understood, however, that if desired we may employ merely the lower mold l uithout the plunger 4-, allowing the lens to set down onto the mold by its own weight in place of being pressed there aflainsl. In either event we have shown as disposed at the side of the mold and plunger tln liquid supply pipe 7 having the spray nozzles 8 and 9 directed respectively toward the absorbent coatings 3 and 6 of the mold l and plunger 4, whereby these coatings may be readily sprayed to saturate the same with suitable moisture of Water, oil or the like, as may be preferred. It will he understood, however, that in the carrying out of our process it is not necessary to employ the spray nozzles, since the absorbent coatings may be moistened by the use of a. sponge, brush or in any other suitable manner.

In the further carrying out of our process the lens is suitably heated, as by being )lacod within the furnace or heater 10. n the event that it desired to change the shape of a lens already ground and olished, as the lens blank 11 shown in Fig. I for example, the blanl: in place of being rested in the oven or heater with its polished surface in contact with the floor or grating of the oven, may be suspended as by the tongs 12 engaging the edges of the lenses and held on a. suitable rest 13, a spring 14 holding the jaws of the ton in clamping engagement with the edges of the lens. In this manner the lens is heated and after bein heated is moved by the tongs and place upon the mold 1, being then if desired engaged by the plunger 4 to firmly press the lens down against the mold and shape the upper surfaceof the lens, as should e best understood by reference to Fig. III.

Attention is here invited to the fact that in Fig. III the mold l is shown as having the depending stem 15 surrounded by the spring 16, allowing the mold to yield downward within the tubular casing or shell 17 which serves to engage the edges of the lens blank 11 to prevent spreading thereof under the pressure of the plunger 4 so that the upper and lower surfaces of the lens will both have the desired curve, while upon raising of the plunger 4 the spring 16 will shift the mold upward to bring the lens above the shell 17.

It is to be understood that in the carrying out of our process, the absorbent coating of the mold that both mold and plunger are employed, are suitably saturated. When the spray nozzles are employed for this purpose the coatings may if desired be saturated with steam, thus raising the temperature of the mold nearer that of the glass so there will be less liability of cracking or strain on the blank on account of the heated plastic blank being suddenly brought into contact with the cold mold or a hen ed oil may he used for the saturation. In any event, the absorbent surfaces having been saturated the blank is placed in position and if a plunger is uscd theplunger 4 is brought down, as illustrated in Fig. III, in which the mold has been pushed downward by the blank and plunger within the shell 17 which engages the side walls of the blank to limit its spreading movement and insure the proper thickness and upper and lower curves of the blank. In Fig. III the action of our improved process has been exaggerated for purposes ofillustration. By reference to this figure it will be noted that between the surface 3 and the lens blank 11 and between the surface 6 and the lens blank 11 is a cushion of vapor 18, which it is true in actual practice will be so thin as to be in'ipcroeptiblc, but which at the same time will place a thin film or covering between the surfaces 3 and (i and the fa es of the lens, this vapor being gone eratcd by the approach of the hot blank 1.1 to the surfaces, and continuing to be generated until the surfaces have been so cooled that they will no longer be in any Wise injured by contact with the absorbent coatings 3 and 6.

It will be appreciated, however, that inasmuch as the vapor films conform exactly to the curve or shape of the absorbent surfaces from which they rise, that the lens blank will be properly molded to the exact desired curve and at the same time will ac quire what may be termed a fire polish, or in other words, a high glazed polish suitable for optical purposes.

It will be noted in connection WithFig. III that we have shown a treadle or the like coupled to actuate the plunger 4 while there is an operating arm 19 associated with the main treaxlle 20 in such manner that presand of the plunger, in the event sure of the foot on the treadle to depress the plunger will serve to temporarily open the controlling valve 21 for the spray supply lines and temporarily sp ay the sur aces 3 and 6.

Likewise, as the plunger is raised, and in order to insure substantially uniform cooling of the lens blank as it is raised upward by the action of the 'sprin 16 on the mold 1, we have placed on the s iell 17 the blower nozzle or nozzles 22 controlled by the valve 23 and adapted to project a current or blast of air across the lens to suitably cool same. This blast is controlledby the valve handle 24 havin pivoted thereto the latch end 25 engaged y the pin 26 on the plunger as the plun er rises to temporarily open the valve and low it to slip off the pin 26 and close before the plunger reaches its upper limit of movement, the pivotal connection between the valve handle 24: and member 25 being such that the plunger will swing the member downward on its pivot 11 on depression of the plunger without actua ing the air spray, a spring 27 returning it to raised posltion where it will been aged by the pin on the plunger on upward movement of the plung In Fig. V we have illustrated one modification of our process, in which the plunger member 4: is suitably rotatably mounted and driven with a spinning movement so that the lens is placed on the mold or support 1 and the spinning lunger with saturated absorbent surface 6 rought down onto the lens s inning around over it to insure correct 5 aping of its upper exposed surface.

From the foregoing description taken in connection with the accom anying drawings, the generic features 0 our improved process should be readily ap arent, and it will be seen that broadl spea ing the process consists in the suitable preparation of a mold having an absorbent surface or surfaces which may be adapted to give off a steam or like protecting vaiplgr to form a film protecting the surface In contact on bringin of a heated lens blank into proximity t ereto, in suitably heating the lens 7 blank and placing the blank above the mold and in causing the blank to conform to the shape of the mold, either by its own weight as it is placed thereon in heated plastic con-- dition, or by the application of pressure thereto, or, if preferred, by making the mold in such shape that the lens may be blown from molten glass directly against the mold surface, the essential features in an event hein the heating or bringing of t e lens blan to a plastic condition and the placing of the plastic glass in such relation to a vapor protected mold. that the glass will receive the sh" e of the mold and at the same time have a l i 're polished surface or its own polished surface preserved on account of the protecting vapor, preventing actual contact between the surface of the lens and the surface of the mold, while the lens surface is in lastic or impression receiving condition.

e claim:

1. The process of forming an ophthalmic lens, conslsting in heating the glass stock, preparing molding surfaces therefor by moistening the surfaces, placing the glass stock between the surfaces while in heated condition, bringin the moistened surfaces toward the glass w iereby a cushioning film is provided preservin the fire polish of the glass while shaping tile stock to correspond with the shape of the mold, withdrawing the shaping pressure and projecting an air blast on the molded lens.

2. The process of forming an ophthalmic lens, consisting in heating the glass stock, bringing the glass stock and a mold into close proximit one with the other, producing a vapor film between the adjacent surfaces of the mold and glass stock, withdrawing the shaping pressure and projecting an air blast on the molded lens.

In testimony whereof we affix our signatures in the presence of two witnesses.

EDGAR D. TILLYER. HARRY H. STYLL.

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